Private and commercial properties include waste water drainage systems for draining waste water into public sewers. The water bill received by an owner or a tenant of a property may be estimated. The estimation may depend upon the amount of water that is used by the property and the surface area of land associated with the property, rather than an accurate assessment of the amount of water that is drained away from the property.
Waste water from some properties may include more impurities than waste water from others. Waste water from some properties may include illegal discharge such as suspended metals (for example, chrome, zinc or copper) and paint. At present, many water companies are unable to assess which properties these are and consequently, the water companies are unable to take appropriate action.